Tidal area insect control method

ABSTRACT

A target insect in a tidal area is controlled by: choosing a treatment area in a tidal area; selecting an appropriate control agent; determining an appropriate depth below the surface of the treatment area for the delivery of the control agent; determining an appropriate application rate; and delivering the appropriate control agent to at least a portion of the treatment area at the appropriate depth and at the appropriate rate. Treatment may be directed at the larval stage of the target insect with the treatment area between a mean lower low tide demarcation and a mean higher high tide demarcation. The control agent may be delivered through passageways extending along a plurality of downwardly and rearwardly extending agent delivery knives.

CROSS-REFERENCE TO OTHER APPLICATIONS

None.

FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

None.

BACKGROUND OF THE INVENTION

Effective control of sand flies assumes increased importance when insectpopulations are not controlled, and especially when allowed to increase,in areas frequented by larger numbers of people or animals, such as inresort areas. Rainfall, tidal intrusion and fluctuations maysignificantly increase pestiferous insect populations. Inadequatecontrol measures coupled with an influx of visitors increasehuman/insect interactions increasing the level of nuisance. In someinstances, those people who are sensitive or are allergic, view bitingflies as an added psychological burden. Regardless of personal tolerancelevels to biting flies, the tranquility of any beach front property isshattered when residents or guests are assaulted by swarms of theseblood-feeding insects.

BRIEF SUMMARY OF THE INVENTION

The present invention is directed to methods for sand fly control withintidal areas. Tidal areas are those areas that are periodically coveredby water and exposed to the air due to the rising and falling of tides.The tidal areas may be along a beach or in other areas such as mudflats.

The present invention is directed to a method for controlling a targetinsect in a tidal area comprising the following steps: (a) choosing atreatment area in a tidal area for a target insect; (b) selecting anappropriate control agent for the target insect; (c) determining anappropriate depth below the surface of the treatment area for thedelivery of the control agent; (d) determining an appropriateapplication rate for the control agent; and (e) delivering theappropriate control agent to at least a portion of the treatment area atthe appropriate depth and at the appropriate rate. In some embodimentsin the treatment area choosing step is carried out for the larval stageof the target insect. The treatment area may be found between a meanlower low tide demarcation and a mean higher high tide demarcation. Thecontrol agent may be a liquid or a flowable solid control agent. Thecontrol agent may be delivered through passageways extending along aplurality of downwardly and rearwardly extending agent delivery knives,and out of the passageways through at least one exit opening. Thecontrol agent delivering step may be carried out using an agentapplication system comprising: a vehicle; an applicator frame assemblycoupled to the vehicle, the applicator frame assembly comprisingdownwardly and rearwardly extending agent delivery knives; and a controlagent delivery system supported by at least one of the vehicle and theapplicator frame assembly, the control agent delivery system comprisingagent delivery passageways having at least one exit opening along theagent delivery knives through which the control agent passes.

Various features and advantages of the invention will appear from thefollowing description in which the preferred embodiments have been setforth in detail in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an overall top, rear, left side view of an agent applicationsystem used to apply a control agent to a tidal area to control a targetinsect;

FIG. 2 is a left side, top, front view of the application frame assemblyof FIG. 1; and

FIG. 3 is a simplified side cross-sectional view illustrating a portionof an agent delivery knife extending beneath the surface of a tidalarea.

DETAILED DESCRIPTION OF THE INVENTION

The following description of the invention will typically be withreference to specific structural embodiments and methods. It is to beunderstood that there is no intention to limit the invention to thespecifically disclosed embodiments but that the invention may bepracticed using other features, elements, methods and embodiments.

FIGS. 1 and 2 illustrate an agent application system 10 comprisingbroadly a vehicle 12, an applicator frame assembly 14 secured to andpulled by the vehicle, and two different types of control agent deliverysystems. The first type of control agent delivery system is liquidcontrol agent delivery system 16 mounted to and carried by frameassembly 14. The other type of control agent delivery system is aflowable solid control agent delivery system 18 supported by vehicle 12.

Frame assembly 14 comprises a frame 20 including a front portion 22 anda rear portion 24. Liquid control agent delivery system 16 is mounted tofront portion 22. A set of rearwardly swept agent delivery knives 26 aresecured to rear portion 24 and extended downwardly and rearwardly fromthe rear portion. Agent delivery knives 26 are configured to extendbelow the surface 28 of a tidal area so that the distal end or tip 32extends below surface 28. See FIG. 3. Although agent delivery knives 26preferably have the rearwardly swept shape illustrated, knives 26 couldalso have other downwardly and rearwardly extending configurations, suchas straight, doglegged (two straight sections joined at an angle), or acombination of straight and curved.

Tidal areas are areas in which the tide covers and uncovers the surfaceof the ground, be it a sandy beach, a mud flat, or other areas. Meantidal area, as used in this application, refers to the region betweenthe mean lower low tide demarcation and the mean higher high tidedemarcation. The mean tidal areas typically contain the primary feedingzones for sand fly larvae so that the sand fly larvae are often found ingreat numbers in the mean tidal areas.

Applicator frame assembly 14 also comprises several tubes 34 definingpassageways for the passage of a control agent therethrough. Each tube34 has an exit opening 36, typically at the distal end of the tube. Ifdesired tube 34 may have more than one exit opening 36, some or all ofwhich are spaced apart from the distal end of the tube. Rear portion 24of frame 20 also has a number of downwardly extending raking tines 38used to rake surface 28 of the tidal area. When the tidal area is asandy beach, this helps to smooth out the sandy surface and also helpsto collect debris. Raking may also help to distribute the control agentthat is delivered through tubes 34 as discussed in more detail below.

In the embodiment of FIGS. 1 and 2, tubes 34 of frame assembly 14 areconnected to a liquid agent manifold 40 supported by frame 20. Manifold40 is supplied a liquid control agent from a tank 42 of liquid controlagent delivery system 16. Tank 42 is stabilized by a generally U-shapedframe 43, frame 43 not shown in FIG. 2 for clarity of illustration. Tank42 is pressurized by a pressurization pump, not shown. Liquid controlagent from tank 42 passes through a supply line 46 connecting tank 42 tomanifold 40, through inlets 48 of tubes 34, through passageways formedin tubes 34 and out through exit openings 36. The depth 50 of exitopening 36 below surface 28 of the tidal area is of particularsignificance. That is, depth 50 is chosen to be the average or meandepth of the sand, mud, or other strata where sand fly larvae can befound. It has been found that selecting depth 50 to be about 1.5 inchesto 6 inches (3.81 cm to 15.24 cm), and preferably about 3 inches (7.62cm), is effective.

Applicator frame assembly 14 is raised and lowered using a lift cable 52connected to a winch 54, the winch being mounted to a mounting rack 58secured to vehicle 12. Frame assembly 14 pivots about a pivot connection56 at a lower, outer end of mounting rack 58. In addition to using liftcable 52 to adjust depth 50, depth 50 can also be controlled byadjusting the angle between rear portion 24 and front portion 22 offrame 20 through the use of mounting bolts 60. Further, the length,number and shape of tines 38 and the angle of tines 38 relative to rearportion 24 can also be adjusted to help control depth 50.

Flowable solid control agent delivery system 18 includes a hopper 62holding the flowable solid control agent for delivery through an outletfitting 64. When it is desired to use a granular, or other flowablesolid control agent, instead of a liquid control agent, a manifold inletof a flowable solid manifold, not shown, is connected to outlet fitting64. Inlets 48 of tubes 34 are connected to the flowable solid manifoldto permit the flowable solid control agent to be directed through tubes34 and out exit openings 36 passing beneath surface 28 of the tidalarea. In some situations delivery system 18 can be used to disperse acontrol agent, often in a fine particulate or powdered form, aboveground by connecting fitting 64 to a suitable distribution device. See,for example, U.S. Pat. No. 4,799,831; see also products sold by Arro-GunSpray Systems, LLC of Reno, Nev. as Mozzie Gas Foggers and MozzieElectric Foggers, products sold by ADAPCO of Stanford, Fla., andproducts sold by London Fog Incorporated of Long Lake, Minn.

In use, the mean tidal area for the area being treated is determined.Then the treatment area, typically within the mean tidal area, is chosenbased upon where the primary feeding zone for the sand fly larvae, orother target insect, is or is expected to be. The treatment area may be,for example, a central portion of the mean tidal area or all of the meantidal area. In some situations in the treatment area may encompass allor part of the mean tidal area and regions outside of the mean tidalarea.

The present invention can use a wide variety of commercially availablecontrol agents. However, some embodiments use an integrated biorationalcontrol program that focuses on safe and sane use of cost effectivemethods and principles in accordance with the guidelines recognized byinternational organizations such as the Centers for Disease Control andPrevention, United States Environmental Protection Agency, and the WorldHealth Organization. This control strategy makes it a priority toprovide a harmony among sometimes competing interests, including costand environmental factors, while achieving effective control. A fullyintegrated program incorporates the most effective products availablethat are cost effective, easy to use, environmentally friendly andcompatible with the application equipment.

Balanced control methodologies are most successful when combined withnaturally biodegradable materials using the most advanced technology inapplication techniques and equipment. Agent application system 10 canuse a wide variety of control agents in either liquid or granularformulations. A control agent that is particularly suited forcontrolling the larval stage of sand flies contains the activeingredient methoprene. Methoprene acts as an insect growth regulatormimic that inhibits the emergence of the adult biting form of sandflies. Methoprene-containing control agents are often preferred becauseof methoprene's low environmental impact with no affect on humans, fish,birds or wildlife. Methoprene-containing products are therefore isparticularly suited for sensitive areas, such as public beaches. Inaddition, methoprene-containing products are often consistentformulations providing long-term control while saving on labor costs.

Application rates of both liquid and granular formulations of methoprenehave been calculated and tested in the field. The use ofmethoprene-containing formulations has proven to be effective inreducing adult sand fly populations on resort properties.Methoprene-containing control agents may be applied by being deliveredbeneath the surface area 28 of the mean tidal area over the chosentreatment area. For example, control agents may be incorporated into abeach sand strata layer where sand fly larvae are found, such as about7.6 cm below surface 28 of the tidal area. By presenting the controlagent at the proper concentration and depth in the sand column, watermovement caused by tidal fluctuations coupled with hydrostatic pressure,serve to evenly disperse the active ingredient throughout the treatmentarea within the tidal area, effectively providing control. Field trialsto determine dosage mortality concentrations have been conducted andresults have shown that application rates of Altosid Liquid Larvicide(ALL 5%) will provide effective control when applied at 6 fluid ouncesper acre (439 ml per hectare). This application rate results in theconcentration of the active ingredient methoprene at 7.465 ppb.Additionally, Altosid Single Brood Granules (SBG) application rates havebeen determined to be 10 pounds per acre (22.4 kg per hectare). Altosidproducts are available from Wellmark International. This applicationrate results in the concentration of the active ingredient methoprene at7.407 ppb. These applications result in the concentration of the activeingredient methoprene at about 7.4 ppb. Other application rates may alsobe effective.

Other modification and variation can be made to the disclosedembodiments without departing from the subject of the invention asdefined in following claims.

Any and all patents, patent applications and printed publicationsreferred to above are incorporated by reference.

1. A method for controlling a sand fly in a tidal area comprising: (a)choosing a treatment area within a mean tide zone defined by a lower lowtide demarcation and a higher high tide to demarcation, the treatmentarea containing a primary feeding zone for the larval stage of a targetinsect, the target insect being a sand fly; (b) selecting amethoprene-containing control agent for control of the target insect;(c) selecting about 3.81 to 15.24 cm as an appropriate depth below thesurface of the treatment area for the delivery of the control agent; (d)selecting an application rate for the control agent to result in aconcentration of methoprene of about 7.4 ppb; and (e) delivering thecontrol agent to at least a portion of the treatment area at theappropriate depth and at the application rate, the control agentdelivering step being carried out using an agent application systemcomprising: a vehicle; an applicator frame assembly coupled to thevehicle, the applicator frame assembly comprising rearwardly swept agentdelivery knives; and a control agent delivery system supported by atleast one of the vehicle and the applicator frame assembly, the controlagent delivery system comprising agent delivery passageways having atleast one exit opening along the agent delivery knives through which thecontrol agent passes.
 2. A method according to claim 1 wherein theappropriate depth selecting step comprises selecting about 7.6 cm as theappropriate depth.